For example, in a broadcasting receiving apparatus for receiving a television broadcasting or an information reproducing apparatus for reproducing information recorded on an information recording medium, when an audio signal is reproduced from the received broadcasting signal or the signal read from the information recording medium, sound quality control processing is performed on the audio signal to further enhance sound quality.
In this case, the type of the sound quality control processing is changed according to whether the received audio signal is a speech signal representing a human's speaking voice and the like or a music (non-speech) signal representing a music. For example, sound quality control processing is performed on a speech signal to clarify speech-sounds by emphasizing centrally-localized components thereof, as in talking-scene and live sport broadcasts. Thus, sound quality is improved. On the other hand, sound quality control processing is performed on a music signal to provide spaciousness with an emphasized stereophonic feeling.
For example, it is considered to determine whether a received audio signal is a speech signal or a music signal, and to then perform associated sound quality control processing according to a determination result. JP-H07-013586-A discloses a configuration in which acoustic signals are classified into three types of signals, i.e., a “speech” signal, a “non-speech” signal and an “undefined” signal by analyzing the zero-crossing counts, power variations and the like of input acoustic signals, and in which the frequency characteristics corresponding to the acoustic signal are controlled as follows. That is, when the acoustic signal is determined as a “speech” signal, the frequency characteristics corresponding to the acoustic signal are controlled to emphasize those in a speech band. When the acoustic signal is determined as a “non-speech” signal, the frequency characteristics are controlled to be flat. When the acoustic signal is determined as an “undefined” signal, the frequency characteristics are controlled to maintain characteristics determined by the last determination.
However, since speech signals and music signals are frequently mixed into actual audio signals, it was difficult to discriminate therebetween and to perform suitable sound quality control processing on an audio signal.